/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 1999-2002,2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.sun.org.apache.xerces.internal.dom;

import org.w3c.dom.DOMException;
import org.w3c.dom.DOMImplementation;
import org.w3c.dom.Document;
import org.w3c.dom.DocumentType;
import org.w3c.dom.Element;


/**
 * The DOMImplementation class is description of a particular
 * implementation of the Document Object Model. As such its data is
 * static, shared by all instances of this implementation.
 * <P>
 * The DOM API requires that it be a real object rather than static
 * methods. However, there's nothing that says it can't be a singleton,
 * so that's how I've implemented it.
 *
 * @xerces.internal
 * @since PR-DOM-Level-1-19980818.
 */
public class DOMImplementationImpl extends CoreDOMImplementationImpl
    implements DOMImplementation {

  //
  // Data
  //

  // static

  /**
   * Dom implementation singleton.
   */
  static DOMImplementationImpl singleton = new DOMImplementationImpl();

  //
  // Public methods
  //

  /**
   * NON-DOM: Obtain and return the single shared object
   */
  public static DOMImplementation getDOMImplementation() {
    return singleton;
  }

  //
  // DOMImplementation methods
  //

  /**
   * Test if the DOM implementation supports a specific "feature" --
   * currently meaning language and level thereof.
   *
   * @param feature The package name of the feature to test. In Level 1, supported values are "HTML"
   * and "XML" (case-insensitive). At this writing, com.sun.org.apache.xerces.internal.dom supports
   * only XML.
   * @param version The version number of the feature being tested. This is interpreted as "Version
   * of the DOM API supported for the specified Feature", and in Level 1 should be "1.0"
   * @return true iff this implementation is compatable with the specified feature and version.
   */
  public boolean hasFeature(String feature, String version) {

    boolean result = super.hasFeature(feature, version);
    if (!result) {
      boolean anyVersion = version == null || version.length() == 0;
      if (feature.startsWith("+")) {
        feature = feature.substring(1);
      }
      return (
          (feature.equalsIgnoreCase("Events")
              && (anyVersion || version.equals("2.0")))
              || (feature.equalsIgnoreCase("MutationEvents")
              && (anyVersion || version.equals("2.0")))
              || (feature.equalsIgnoreCase("Traversal")
              && (anyVersion || version.equals("2.0")))
              || (feature.equalsIgnoreCase("Range")
              && (anyVersion || version.equals("2.0")))
              || (feature.equalsIgnoreCase("MutationEvents")
              && (anyVersion || version.equals("2.0"))));
    }
    return result;
  } // hasFeature(String,String):boolean


  /**
   * Introduced in DOM Level 2. <p>
   *
   * Creates an XML Document object of the specified type with its document
   * element.
   *
   * @param namespaceURI The namespace URI of the document element to create, or null.
   * @param qualifiedName The qualified name of the document element to create.
   * @param doctype The type of document to be created or null.<p>
   *
   * When doctype is not null, its Node.ownerDocument attribute is set to the document being
   * created.
   * @return Document        A new Document object.
   * @throws DOMException WRONG_DOCUMENT_ERR: Raised if doctype has already been used with a
   * different document.
   * @since WD-DOM-Level-2-19990923
   */
  public Document createDocument(String namespaceURI,
      String qualifiedName,
      DocumentType doctype)
      throws DOMException {
    if (namespaceURI == null && qualifiedName == null && doctype == null) {
      //if namespaceURI, qualifiedName and doctype are null, returned document is empty with
      //no document element
      return new DocumentImpl();
    } else if (doctype != null && doctype.getOwnerDocument() != null) {
      String msg = DOMMessageFormatter
          .formatMessage(DOMMessageFormatter.DOM_DOMAIN, "WRONG_DOCUMENT_ERR", null);
      throw new DOMException(DOMException.WRONG_DOCUMENT_ERR, msg);
    }
    DocumentImpl doc = new DocumentImpl(doctype);
    Element e = doc.createElementNS(namespaceURI, qualifiedName);
    doc.appendChild(e);
    return doc;
  }


} // class DOMImplementationImpl
